KR20190111772A - Electrolyte liquid for electrochemical device and electrochemical device - Google Patents

Abstract

The present invention provides an electrolyte liquid for an electrochemical device capable of improving high temperature reliability of the electrochemical device, and the electrochemical device having the same. The electrolyte liquid for the electrochemical device comprises: an electrolyte liquid, wherein LiPF_6 of 0.8 mol/L or more and 1.6 mol/L or less is included as an electrolyte to a ring type carbonate solvent; and chain type carbonates, wherein the addition amount with respect to the electrolyte is 0.1 wt% or more and less than 10.0 wt%.

Description

ELECTROLYTE LIQUID FOR ELECTROCHEMICAL DEVICE AND ELECTROCHEMICAL DEVICE

The present invention relates to an electrolytic solution for an electrochemical device and an electrochemical device.

Electrochemical devices such as an electric double layer capacitor or a lithium ion capacitor using a nonaqueous electrolyte have a high electrolysis voltage of a solvent, and thus can withstand high voltages and can accumulate large energy.

In recent years, electrochemical devices are required to secure reliability in a high temperature state. Regarding high temperature reliability, various characteristics of the cell deteriorate due to the reduction of an electrolyte solution in which an anion such as PF ₆ ⁻ , which is an electrolyte, decomposes such as hydrogen fluoride to form a high-resistance coating near the negative electrode. It is thought that.

In order to solve the above problem, for example, Patent Document 1, lithium tetrafluoroborate as the lithium bis borate (LiBF ₄₎ (pentafluoroethyl sulfonyl) already lithium with an electrolyte solution mixed with de (LiBETI) at a predetermined ratio An ion battery is disclosed. Patent Literature 2 discloses a lithium ion battery using an electrolyte solution in which part of LiBF ₄ is added to lithium hexafluorophosphate (LiPF ₆ ) in order to improve high temperature storage characteristics. Patent document 3 proposes the electrolyte solution which can improve the cycling characteristics of a lithium ion battery, and the characteristic after a short-term high temperature holding test by adding a methylenebissulfonate derivative to the electrolyte solution using the mixed solvent of ethylene carbonate and ethyl methyl carbonate, and have.

Japanese Patent Laid-Open No. 2001-236990 Japanese Patent Publication No. 2003-346898 International publication 2012/017999

When using an electrolyte solution in which LiBF ₄ and LiBETI are mixed at a constant ratio as in Patent Literature 1, the stability of the electrolyte solution at high temperature is improved compared to the electrolyte solution using LiPF ₆ as a result of the high heat resistance of the electrolyte and the high electrical conductivity of LiBETI. However, LiBETI has a problem in long-term reliability because the positive electrode potential corrodes the current collector foil (aluminum) in the vicinity of 4V (vs Li / Li ⁺ ).

In Patent Document 2, using an electrolyte mixing some LiBF ₄ to LiPF _6, but is disclosed to suppress the deterioration of the battery after high-temperature storage, in a high temperature (60 ℃) Since LiPF ₆ is not so heat is not decomposed even if the effect of , Thermal decomposition of LiPF ₆ can not be ignored in an environment of 85 ° C., and improvement in battery reliability cannot be predicted.

In patent document 3, when high temperature is maintained over a long period of time, problems such as the fact that a film on the surface of the negative electrode is further formed, a point that decomposition of the electrolyte solution, and the like may occur.

This invention is made | formed in view of the said subject, and an object of this invention is to provide the electrolyte solution for electrochemical devices which can improve the high temperature reliability of an electrochemical device, and the electrochemical device provided with it.

The electrolytic solution for an electrochemical device according to the present invention is an electrolytic solution containing LiPF ₆ of 0.8 mol / L or more and 1.6 mol / L or less as an electrolyte in a solvent of a cyclic carbonate, and an addition amount of 0.1 wt% or more and 10.0 to the electrolyte solution. and less than wt% chain carbonate.

In the electrolytic solution for electrochemical devices, at least one of carbonate ester, sulfonic acid ester, and lithium oxalato complex salt may further be included as an additive having an amount of 0.1 wt% or more and 5.0 wt% or less added to the electrolytic solution. .

In the electrolytic solution for electrochemical devices, the carbonate ester may be at least one of vinylene carbonate and fluoroethylene carbonate.

In the electrolyte solution for electrochemical devices, the sulfonic acid ester may be bis (ethane sulfonic acid) methylene.

In the electrolytic solution for an electrochemical device, the oxalato complex salt may be at least one of lithium bis (oxalato) borate, difluorobis (oxalato) lithium phosphate, and tetrafluorooxalato lithium phosphate.

In the electrolytic solution for electrochemical devices, the chain carbonate may be at least one of dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate.

The electrochemical device which concerns on this invention is equipped with the electrical storage element by which the positive electrode and the negative electrode were laminated | stacked through the separator, The active material of the said positive electrode, the active material of the said negative electrode, or the said separator, The electrolyte solution for electrochemical devices in any one of said It is characterized by being impregnated.

According to this invention, the electrolytic solution for electrochemical devices which can improve the high temperature reliability of an electrochemical device, and the electrochemical device provided with the same can be provided.

1 is an exploded view of a lithium ion capacitor.
2 is a cross-sectional view of the stacking direction of the positive electrode, the negative electrode, and the separator.
3 is an exploded view of a lithium ion capacitor.
4 is an external view of a lithium ion capacitor.
5 is a diagram illustrating test results.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment is described, referring drawings.

(Embodiment)

First, a lithium ion capacitor will be described as an example of an electrochemical device. 1 is an exploded view of a lithium ion capacitor 100. As illustrated in FIG. 1, the lithium ion capacitor 100 includes a power storage element 50 having a structure in which the positive electrode 10 and the negative electrode 20 are wound through the separator 30. The electrical storage element 50 has a substantially cylindrical shape. The lead terminal 41 is connected to the positive electrode 10. The lead terminal 42 is connected to the negative electrode 20.

2 is a cross-sectional view of the stacking direction of the positive electrode 10, the negative electrode 20, and the separator 30. As illustrated in FIG. 2, the positive electrode 10 has a structure in which a positive electrode electrode layer 12 is laminated on one surface of the positive electrode current collector 11. The separator 30 is laminated on the positive electrode layer 12 of the positive electrode 10. The negative electrode 20 is laminated on the separator 30. The negative electrode 20 has a structure in which the negative electrode electrode layer 22 is laminated on the surface of the negative electrode current collector 21 on the positive electrode 10 side. The separator 30 is laminated on the negative electrode current collector 21 of the negative electrode 20. In the electrical storage element 50, the lamination unit of these positive electrode 10, the separator 30, the negative electrode 20, and the separator 30 is wound. In addition, the positive electrode layer 12 may be provided on both surfaces of the positive electrode current collector 11. The negative electrode layer 22 may be provided on both surfaces of the negative electrode current collector 21.

As illustrated in FIG. 3, the lead-out terminal 41 and the lead-out terminal 42 are respectively inserted into two through-holes of the substantially cylindrical sealing rubber 60 having the same diameter as the power storage element 50. . In addition, the electrical storage element 50 is accommodated in the bottomed substantially cylindrical container 70. As illustrated in FIG. 4, the sealing rubber 60 is caulked around the opening of the container 70. Thereby, the sealing property of the electrical storage element 50 is maintained. The nonaqueous electrolyte is sealed in the container 70 and impregnated with the active material of the positive electrode 10, the active material of the negative electrode 20, or the separator 30.

(Positive electrode)

The positive electrode current collector 11 is a metal foil, for example, aluminum foil or the like. This aluminum foil may be a foil with a hole. The positive electrode layer 12 should have a well-known material and structure used for the electrode layer of an electric double layer capacitor or a redox capacitor, For example, polyacene (PAS), polyaniline (PAN), activated carbon, carbon black, graphite, It contains active materials, such as carbon nanotubes, and contains other components, such as a conductive support agent and a binder which are used for electrode layers, such as an electric double layer capacitor, as needed.

(Negative)

The negative electrode current collector 21 is metal foil, for example, copper foil. This copper foil may be a foil with a hole. The negative electrode layer 22 contains active materials such as non-graphitized carbon, graphite, tin oxide, silicon oxide, and the like, and includes conductive aids such as carbon black and metal powder, polytetrafluoroethylene (PTFE), and poly Binders, such as vinylidene fluoride (PVDF) and styrene butadiene rubber (SBR), are also included as needed.

(Separator)

The separator 30 is provided between the positive electrode 10 and the negative electrode 20, for example, to prevent a short circuit accompanying the contact between these two electrodes. The separator 30 forms the electrically conductive path | route between electrodes by hold | maintaining a nonaqueous electrolyte solution in a vacancy. As a material of the separator 30, porous cellulose, polypropylene, polyethylene, a fluororesin, etc. can be used, for example.

In addition, when encapsulating the electrical storage element 50 and the nonaqueous electrolyte in the container 70, the lithium metal sheet is electrically connected to the negative electrode 20. Thereby, while lithium of a lithium metal sheet dissolves in a nonaqueous electrolyte, lithium ion is pre-doped to the negative electrode layer 22 of the negative electrode 20. As a result, in the state before charging, the potential of the negative electrode 20 is lowered by, for example, about 3 V as compared to the potential of the positive electrode 10.

In addition, in this embodiment, although the lithium ion capacitor 100 has the structure which the electrical storage element 50 of the winding structure was enclosed in the cylindrical container 70, it is not limited to that. For example, the electrical storage element 50 may have a laminated structure. In addition, the container 70 in this case may be a rectangular can or the like.

(Non-aqueous electrolyte)

The nonaqueous electrolyte solution can be prepared by dissolving an electrolyte in a nonaqueous solvent and further adding an additive. First, cyclic carbonate is used as the nonaqueous solvent. Cyclic carbonate is propylene carbonate (PC), ethylene carbonate (EC), etc. which are cyclic carbonate. Since cyclic carbonate has high dielectric constant, it has the property which melt | dissolves lithium salt well. Moreover, the nonaqueous electrolyte which used cyclic carbonate for a nonaqueous solvent has high ionic conductivity. Therefore, when cyclic carbonate is used as the nonaqueous solvent, the initial characteristics of the lithium ion capacitor 100 become good. In addition, when cyclic carbonate is used as a nonaqueous solvent, after the film is formed on the negative electrode 20, sufficient electrochemical stability at the time of operation of the lithium ion capacitor 100 is realized.

LiPF ₆ which is a lithium salt is used for the electrolyte. Since LiPF ₆ has a high dissociation degree among general-purpose lithium salts, LiPF ₆ realizes good initial characteristics (capacity and DCR) of the lithium ion capacitor 100. If the concentration (electrolyte concentration) of the electrolyte in the nonaqueous electrolyte solution is too high, the viscosity of the electrolyte solution rises, so that it takes time until the required amount of ions are supplied to the electrode, so that the initial internal resistance may increase. On the other hand, if the concentration of the electrolyte solution is too low, the required amount of ions may not be supplied to the electrode, or it may take time until the electrode is supplied. Therefore, the initial capacity may decrease and the initial internal resistance may increase. Therefore, an upper limit and a lower limit are set to electrolyte solution concentration. In this embodiment, electrolyte solution concentration shall be 0.8 mol / L or more and 1.6 mol / L or less. It is preferable that electrolyte solution concentration is 1.0 mol / L or more and 1.4 mol / L or less. In addition, in this embodiment, since LiBFTI is not used for electrolyte, corrosion of the positive electrode 10 is suppressed.

(First additive)

Chain carbonate is used as a 1st additive added to a nonaqueous electrolyte solution. The use of the chain carbonate is to increase the capacity retention rate when the lithium ion capacitor 100 is exposed to high temperature and to reduce the internal resistance change. It is considered that this is because the viscosity of the electrolyte is lowered by adding a small amount of the chain carbonate to the electrolyte, and as a result, the film-forming material acts uniformly by the negative electrode 20, whereby a thinner, more homogeneous and firm film is formed. As the chain carbonate, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC) or the like can be used. You may use these in combination as a 1st additive. If the concentration of the first additive in the nonaqueous electrolyte solution is too low, it becomes difficult to sufficiently obtain the effect of the first additive. Therefore, a lower limit is set to the density | concentration of the 1st additive in a nonaqueous electrolyte solution. On the other hand, if the concentration of the first additive in the nonaqueous electrolyte solution is too high, dissociation of LiPF _{6 in} the electrolyte solution is disturbed, and there is a possibility that the thermal decomposition of LiPF ₆ is promoted at a high temperature. Therefore, an upper limit is set to the density | concentration of the 1st additive in a nonaqueous electrolyte solution. In this embodiment, the density | concentration of the 1st additive in a nonaqueous electrolyte solution shall be 0.1 wt% or more and less than 10.0 wt%. Moreover, it is preferable that it is 9.0 wt% or less, and, as for the density | concentration of the 1st additive in a non-aqueous electrolyte solution, it is more preferable that it is 5.0 wt% or less. Moreover, it is preferable that it is 0.5 weight% or more, and, as for the density | concentration of the 1st additive in a non-aqueous electrolyte solution, it is more preferable that it is 1.0 weight% or more.

(Second additive)

In addition to the first additive, at least one of carbonate ester, sulfonic acid ester, and oxalato complex salt of lithium is further added as the second additive in order to further reduce the change in internal resistance when the lithium ion capacitor 100 is exposed to high temperature. You may add. This second additive has a reduction potential higher than that of the nonaqueous solvent of the nonaqueous electrolyte, and acts on the negative electrode 20 to form a stable film. As carbonate ester, vinylene carbonate (VC), fluoroethylene carbonate (FEC), etc. can be used. As sulfonic acid ester, bis (ethane sulfonic acid) methylene (MBES) etc. can be used. Examples of lithium oxalato complex salts include bis (oxalato) lithium borate (LiB (C ₂ O ₄ ) ₂ ), difluorobis (oxalato) lithium phosphate (LiPF ₂ (C ₂ O ₄ ) ₂ ), tetrafluoro Lithium oxalate phosphate (LiPF ₄ (C ₂ O ₄ )); In order to fully acquire the effect of a 2nd additive, it is preferable to set a minimum in 2nd additive concentration. On the other hand, if the concentration of the second additive in the nonaqueous electrolyte solution is too high, a thick film is formed on the negative electrode 20, so that the initial internal resistance is increased and the internal resistance change may be large. Therefore, it is preferable to set an upper limit to the second additive concentration in the nonaqueous electrolyte. In this embodiment, it is preferable that the 2nd additive density | concentration in a nonaqueous electrolyte solution is 0.1 wt% or more, It is more preferable that it is 0.2 wt% or more, It is further more preferable that it is 0.5 wt% or more. Moreover, it is preferable that it is 5.0 wt% or less, as for the 2nd additive density | concentration in a non-aqueous electrolyte solution, it is more preferable that it is 3.0 wt% or less, It is further more preferable that it is 1.0 wt% or less.

In this embodiment, in the nonaqueous electrolyte which uses cyclic carbonate as a nonaqueous solvent and uses LiPF ₆ of 0.8 mol / L or more and 1.6 mol / L or less as electrolyte, the addition amount with respect to a nonaqueous electrolyte is 0.1 wt% or more and 10.0 wt. Since it contains less than% chain carbonate, even when the lithium ion capacitor 100 is exposed to high temperature, a favorable capacity retention rate can be obtained and the internal resistance change can be sufficiently reduced. Therefore, high temperature reliability can be improved.

In addition, in this embodiment, although focusing on the electrolyte solution of a lithium ion capacitor as an electrochemical device, it is not limited to that. For example, other electrochemical devices, such as an electric double layer capacitor, can also be used for the nonaqueous electrolyte solution which concerns on this embodiment as electrolyte solution.

EXAMPLE

According to the said embodiment, the lithium ion capacitor was produced and the characteristic was investigated.

(Example 1)

PAS was used as an active material of the positive electrode 10. A slurry was prepared by using carboxymethyl cellulose and styrenebutadiene rubber as a binder, and the prepared slurry was applied onto a perforated aluminum foil to prepare a sheet. As the active material of the negative electrode 20, non-graphitizable carbon made of a phenol resin raw material was used. A slurry was prepared by using carboxymethyl cellulose and styrene butadiene rubber as a binder, and the prepared slurry was applied onto a copper foil subjected to a perforated process to prepare a sheet. The cellulose separator 30 is sandwiched between these electrodes, the lead terminal 41 is attached to the positive electrode current collector 11 by ultrasonic welding, and the lead terminal 42 is attached to the negative electrode current collector 21. These were wound up and the electrical storage element 50 was fixed with the adhesive tape of polyimide. The sealing rubber 60 was affixed to the produced electrical storage element 50, and it vacuum-dried at about 180 degreeC, the lithium foil was stuck to the negative electrode 20, and the electrical storage element 50 was put into the container 70. Then, with respect to the solution (1.10mol / L) prepared by dissolving LiPF ₆ in PC (100vol%), the addition of 3.0wt% EMC as a first additive, the VC was further added 0.1wt% as the second additive, and the resulting aqueous After inject | pouring electrolyte solution into the container 70, the lithium ion capacitor 100 was produced by caulking the part of the sealing rubber 60. As shown in FIG.

(Example 2)

In Example 2, the amount of VC added was 0.5 wt%. Other conditions were the same as in Example 1.

(Example 3)

In Example 3, the amount of VC added was 1.0 wt%. Other conditions were the same as in Example 1.

(Example 4)

In Example 4, the amount of EMC added was 0.1 wt%. Other conditions were the same as in Example 3.

(Example 5)

In Example 5, the amount of EMC added was 1.0 wt%. Other conditions were the same as in Example 3.

(Example 6)

In Example 6, the amount of EMC added was 5.0 wt%. Other conditions were the same as in Example 3.

(Example 7)

In Example 7, the amount of EMC added was 9.0 wt%. Other conditions were the same as in Example 3.

(Example 8)

In Example 8, 3.0 wt% of DMC was added instead of EMC. Other conditions were the same as in Example 3.

(Example 9)

In Example 9, 3.0 wt% of DEC was added instead of EMC. Other conditions were the same as in Example 3.

(Example 10)

In Example 10, PC (80 vol%) and EC (20 vol%) were used as the nonaqueous solvent. Other conditions were the same as in Example 3.

(Example 11)

In Example 11, 1.0 wt% of FEC was added instead of VC. Other conditions were the same as in Example 3.

(Example 12)

In Example 12, 3.0 wt% of FEC was added instead of VC. Other conditions were the same as in Example 3.

(Example 13)

In Example 13, 5.0 wt% of FEC was added instead of VC. Other conditions were the same as in Example 3.

(Example 14)

In Example 14, 1.0 wt% of MBES was added instead of VC. Other conditions were the same as in Example 3.

(Example 15)

In Example 15, 1.0 wt% of LiB (C ₂ O ₄ ) ₂ was added instead of VC. Other conditions were the same as in Example 3.

(Example 16)

In Example 16, 1.0 wt% of LiPF ₂ (C ₂ O ₄ ) ₂ was added instead of VC. Other conditions were the same as in Example 3.

(Example 17)

In Example 17, 1.0 wt% of LiPF ₄ (C ₂ O ₄ ) was added instead of VC. Other conditions were the same as in Example 3.

(Example 18)

In Example 18, 3.0 wt% of DMC was added instead of EMC and no second additive was added. Other conditions were the same as in Example 1.

(Example 19)

In Example 19, no second additive was added. Other conditions were the same as in Example 1.

(Example 20)

In Example 20, 3.0 wt% of DEC was added instead of EMC and no second additive was added. Other conditions were the same as in Example 1.

(Comparative Example 1)

In Comparative Example 1, neither the first additive nor the second additive was added. Other conditions were the same as in Example 1.

(Comparative Example 2)

In Comparative Example 2, the first additive was not added. Other conditions were the same as in Example 3.

(Comparative Example 3)

In Comparative Example 3, the first additive was not added. Other conditions were the same as in Example 11.

(Comparative Example 4)

In Comparative Example 4, the first additive was not added. Other conditions were the same as in Example 14.

(Comparative Example 5)

In Comparative Example 5, the amount of EMC added was 18.0 wt%. Other conditions were the same as in Example 3.

(Assessment Methods)

After fabricating the lithium ion capacitors of Examples 1 to 20 and Comparative Examples 1 to 5, the capacitance and internal resistance at room temperature were measured as initial characteristics. Then, the float test which continuously charges for 1000 hours at the voltage of 3.8V in 85 degreeC thermostat was performed. After the float test, the cells were allowed to cool to room temperature, the capacitance and the internal resistance were measured, and the rate of change before and after the test was calculated. This result (capacity retention rate and internal resistance change rate) is shown in FIG.

(Initial characteristics)

In Examples 1-20 and Comparative Examples 1-5, the capacitance and internal resistance in initial stage showed the favorable value. This is considered to be because cyclic carbonate was used as a non-aqueous solvent, and the concentration of LiPF ₆ was 0.8 mol / L or more and 1.6 mol / L or less. In addition, from the results of Examples 4 to 7, it was confirmed that the initial internal resistance was lowered as the amount of the first additive added increased.

(High temperature reliability)

In Comparative Example 1, the capacity retention was lowered and the internal resistance change rate was larger. This is considered to be because neither the 1st additive nor the 2nd additive was added to the nonaqueous electrolyte from the comparison result of Example 1 and the comparative example 1. Next, in the comparative example 2, although the fall of the capacity | capacitance retention rate and the increase of the internal resistance change rate were suppressed in the comparison with the comparative example 1, the internal resistance change rate was 200% or more and it did not become small enough. This is considered to be because the 1st additive was not added to the nonaqueous electrolyte solution from the comparison result of Example 3 and the comparative example 2. Next, in the comparative example 3, the fall of the capacity | capacitance retention rate and the increase of the internal resistance change rate were suppressed in the comparison with the comparative example 1, but the internal resistance change rate was 200% or more and it did not become small enough. This is considered to be because the 1st additive was not added to the nonaqueous electrolyte solution from the comparison result with Example 11 and the comparative example 3. Next, in the comparative example 4, the fall of the capacity | capacitance retention rate and the increase of the internal resistance change rate were suppressed in the comparison with the comparative example 1, but the internal resistance change rate was 200% or more and did not become small enough. This is considered to be because the 1st additive was not added to the nonaqueous electrolyte solution from the comparison result of Example 14 and the comparative example 4. Next, in Comparative Example 5, the capacity retention rate was lowered. This is considered to be because the addition amount of a 1st additive was too much from the comparison result of Example 3 and the comparative example 5.

On the other hand, in Examples 1-20, while the fall of capacity retention was suppressed, the internal resistance change rate became small enough (less than 200%). This is a non-aqueous electrolyte containing cyclic carbonate as a non-aqueous solvent and having LiPF ₆ of 0.8 mol / L or more and 1.6 mol / L or less as an electrolyte, wherein the amount of addition to the nonaqueous electrolyte is 0.1 wt% or more and less than 10.0 wt%. It is considered that it contains carbonate.

In addition, when Examples 18 to 20 and Examples 1 to 17 were compared, the internal resistance change rate was smaller in Examples 1 to 17. This is considered to be because in Example 1-17, the 2nd additive was added. From the comparison results of Examples 1 to 17 and Examples 18 to 20, it can be seen that the kind of the first additive and the second additive did not affect.

Moreover, when comparing each result of Examples 1-3, it turns out that it is preferable to make the addition amount of a 2nd additive into 0.5 wt% or more. On the other hand, when comparing each result of Examples 11-13, it turns out that it is preferable to make the addition amount of a 2nd additive into 3.0 wt% or less.

As mentioned above, although the Example of this invention was described in detail, it is not limited to the specific Example which concerns on this invention, In the range of the summary of this invention described in the Claim, various deformation | transformation and change are possible.

10: positive electrode
11: positive current collector
12: positive electrode layer
20: negative electrode
21: negative current collector
22: negative electrode layer
30: separator
41, 42: lead-out terminal
50: power storage element
60: sealing rubber
70: container
100: lithium ion capacitor

Claims (7)

An electrolyte solution containing LiPF ₆ of 0.8 mol / L or more and 1.6 mol / L or less as an electrolyte in a solvent of a cyclic carbonate,
The electrolytic solution for electrochemical devices characterized by the above-mentioned addition amount of the linear carbonate of 0.1 wt% or more and less than 10.0 wt%. The method of claim 1,
The electrolyte solution for electrochemical devices, which further contains at least any one of carbonate ester, sulfonic acid ester, and oxalato complex salt of lithium as an additive of 0.1 wt% or more and 5.0 wt% or less with respect to the said electrolyte solution. The method of claim 2,
The said carbonate ester is at least any one of vinylene carbonate and fluoroethylene carbonate, The electrolytic solution for electrochemical devices characterized by the above-mentioned. The method of claim 2,
The said sulfonic acid ester is bis (ethane sulfonic acid) methylene, The electrolytic solution for electrochemical devices characterized by the above-mentioned. The method of claim 2,
The oxalato complex salt is at least one of lithium bis (oxalato) borate, difluorobis (oxalato) lithium phosphate, and lithium tetrafluorooxalate phosphate, the electrolytic solution for an electrochemical device. The method according to any one of claims 1 to 5,
The chain carbonate is at least one of dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate, wherein the electrolytic solution for an electrochemical device. The positive electrode and the negative electrode are provided with the electrical storage element laminated | stacked through the separator,
The electrochemical device for electrochemical devices as described in any one of Claims 1-5 is impregnated in the active material of the said positive electrode, the active material of the said negative electrode, or the said separator.

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